Understanding water wells

To begin to understand how water wells differ from other construction projects, consider the following: First, let’s compare a water well and its irrigation system to a foundation and its building. Wells and foundations both use the soil beneath the ground to support their needs. While foundations use the strength of the soil it rests on to support the weight of the building it carries, water wells use the soil’s ability to transmit water (water bearing capacity) to support the needs of the irrigation system it feeds. Also, just as a foundation can only provide as much strength to the building as the ground beneath it, a water well can only produce as much water for irrigation as the ground will bear.

These properties, strength and water bearing capacity, respectively are critical for proper foundation and water well design, and therefore must be determined. Strength is determined by various methods depending on the area geology, size, scope and other factors of the foundation project. For example: for a light building, an experienced foundation contractor may only need to perform a visual site inspection to provide a reliable estimate, or may dig shallow test pits to confirm fairly predictable soil strength. For heavier buildings, highly specialized drilling equipment may be necessary to perform deeper, more extensive soils and rock testing (test holes). Engineers may also use standard formulas, existing field data from other projects in the area, or will develop their own testing program to obtain reliable strength data. Engineers also have the ability to redesign the foundation, modify, improve or even disregard the soil’s strength (by setting the foundation on bedrock) altogether to achieve the desired results. The fact is, a suitable foundation for any building can be designed and constructed virtually anywhere no matter how poor the soil conditions are. On the other hand, when it comes to water wells; geologists, hydrologists, well drillers, and other water well professionals do not this advantage; this is what makes water well projects so different from any other construction project.

Unlike foundations that require strength from the ground, wells require water. But, without going through the actual expense of drilling the well, how do we know if water is available? In short, we don’t. Even the most experienced water well professionals will tell you that, no matter how accurate or reliable an areas existing field data (information obtained from other wells in the area) may be, most of the time, they cannot accurately predict a certain flow of water from any proposed well location prior to drilling (this is especially true for “bedrock” or “artesian” wells). For this reason, the actual drilling of the well is to always be considered a “test hole”. Although some test holes are intended only to gather information used to design other larger wells, most test holes will produce water and can serve as a fully functioning water well by installing a suitable pump system to it.

Unlike foundations and other construction projects that use formulas and pre-existing data to assure a positive result, prior to drilling there is no guaranteed positive outcome for a well. This makes drilling the test hole a necessary part of the testing program. This also makes arriving at budgets for the entire project very difficult because there are many different scenarios for each test hole. The budget for the best and worst-case scenarios for any water well project could vary ten-fold or more. With proper project assessment, visual site inspections and by studying existing data this price range can be reduced to three-fold. As the projects become larger or more complicated, the more important it is to develop and manage an initial testing program with a budget of it’s own.

Unfortunately, with water well projects you can’t put together a plan with anticipated drilling depths and water yields and just expect it to happen. Since water wells cannot be designed prior to drilling, and must be designed during their actual construction, one must carefully monitor and manage every well, or test hole, as it is being drilled. Have contingency plans that are based on the results of each well. Be willing and able to evaluate the results, then to re-evaluate and change course without bailing out of the project. Bottom line: You should have clear, logical, informed reasons for the decisions that you make, regardless of the outcome of a single test hole, remembering that a successful well drilling project is not one that goes as planned, but one that is completed, within the budget, and provides you with the amount of water you need.